What's eating you? US study highlights bedbug incest

Thursday, December 8, 2011

File photo of Cimex lectularius, the bed bug.
Image: Piotr Naskrecki for CDC/Harvard.

At the meeting of the American Society of Tropical Medicine and Hygiene, North Carolina State University (NCSU) researchers lead by Coby Schal and Ed Vargo presented preliminary research on the genetic diversity of populations of bedbugs. Their DNA analysis showed the diversity is low within a single building. The researchers discovered that the bugs can inbreed and evolve at the same time.

A part of the research included extensive DNA analysis of genetics of bed bugs in different apartments. The diversity was lower than it would be for a population of most other species. Coby Schal said, "We kept discovering the same thing. Within a given apartment, or even a given building, there was extremely low genetic diversity. In most cases there's just a single female that founded the population."

Another NCSU anthologist Zachary Adelman, not one of the researchers, said that the fact of different strains of bedbugs in the United States east coast "means they're coming into the country from lots of different places".

The discovery shows that pesticides are ineffective if they don't eliminate the entire population. Just a few survivors can produce a new generation within the house or building quickly; and, as the offspring of those surviving pesticide use, pass on their genetic resistance; emphasising Schal's remark that, "[t]he insecticides really need to be robust".

Coby Schal said that for most species, limited diversity causes generic disorders and population does not survive, thus making the discovery a surprise. He said, "But somehow bedbugs are able to withstand the effects of inbreeding, and do quite well." Schal was suggesting that as cockroaches inbreed successfully as well, its success may be related to the species' reliance on humans to relocate from place to place. The research is at preliminary stage, meaning the scientists may carry out more analysis before a final release.